The testing of electronic devices, including discrete components as well as integrated circuits and assemblies such as circuit boards, is important for various reasons. Testing of devices on the wafer can be useful for process verification and control, among other things. Testing of manufactured or partially manufactured devices is important for detecting defects, as well as for purposes such as confirming the provenance of the devices.
Defect detection in integrated circuits (ICs), for example, can be challenging because an IC can have millions of transistors with a feature size less than a micrometer. Therefore, to identify a defect in an IC generally requires extensive failure analysis. In the past, various techniques based on electrical, optical, and thermal properties of ICs have been developed. However, these techniques are quite complex, time-consuming, and costly.
Further, an IC or other circuit component can contain a latent defect (also referred to as a “failure precursor”) that is likely to develop into a defect after a period of use. Conventionally, these latent defects are detected by subjecting the IC or component to reliability testing, during which the device receives high voltage and/or high temperature for a period of time. Reliability testing can be quite time-consuming and can significantly increase the production cost.
Various screening techniques are available for detecting defects or other anomalies in ICs and other circuit components. However, the selection of any screening technique involves tradeoffs among cost, accuracy, discrimination among different anomalies, destructiveness, and other factors. Hence there remains a need for a greater variety of screening techniques, and in particular for techniques that are simple and efficient.